1. Field
Embodiments of the invention relate to phase change memory materials and more particularly to GeAs telluride materials useful for phase change memory applications, for example, optical and electronic data storage.
2. Technical Background
Conventional phase change memory devices utilize materials which can change between two phases having distinct properties. The materials, typically, can change from an amorphous phase to a crystalline phase, and the phases can have considerably different properties, for example, different resistivities, conductivities, and/or reflectivities.
Phase change from an amorphous phase to a crystalline phase can be achieved through heating the amorphous material to a temperature which promotes nucleation, crystal formation, and then crystallization. The phase change back to amorphous can be achieved by heating the crystalline phase above the melting temperature.
Chalcogenide materials, for example, Ge, Sb, and Te alloys are currently used in phase change memory applications such as for storing information in over writable disks.
Several phase change memory materials identified to date have been developed by workers at Matsushita/Panasonic and IBM. Representative materials include compositions on the GeTe—Sb2Te3 join, particularly Ge2Sb2Te5 (GST), and Au, In-doped Sb telluride (AIST). These materials can be cycled on a ˜10 ns time scale between a high conductivity, high reflectivity crystalline phase and a low conductivity, low reflectivity amorphous phase under laser heating or current pulses.
Although some conventional materials such as GST and AIST have good properties for non-volatile memory applications, it would be advantageous to have phase change memory materials that have faster phase transitions and/or longer write/rewrite potential.